The invention relates to the field of radioimaging and more particularly to immunoreagents and methods for detecting neutrophils at the site of occult abscesses.
Hidden infections and inflammations or occult abscesses are difficult to detect by conventional methods. Often an infection in the patient is diagnosed by an elevated white cell count or the presence in the blood of a specific pathogen, but the exact location of the infection can not be found by manual examination. X-ray of the patient is usually not helpful because the infection or inflammation is in soft tissue which is not detected by this method. Delay in detecting occult abscesses delays treatment of the condition and increases the risk of exacerbation and spread of the infection or inflammation.
New methods of detecting occult abscesses which are not time consuming and which accurately locate the infection or inflammation are needed to overcome the difficulties of detecting these conditions by conventional methods.
Radiolabels such as .sup.111 Indium and 6.sup.7 Gallium have been used to make body tissues radiodense and thus appear on X-ray film. This method however lacks specificity and labels many types of tissues. A high background of radioactivity is produced so that the target tissue cannot be distinguished from the background.
Thakur et al., Journal of Nuclear Medicine 18: 1014-1019, (1977) used .sup.111 Indium-oxine to label leukocytes. In this method a sample of the patient's blood is removed and the leukocytes separated from the rest of the blood. The leukocytes are then labeled with .sup.111 Indium oxine and reinjected into the patient. The radiolabeled leukocytes are then allowed to migrate to sites of occult abscesses. The radiolabeled leukocytes are then detected by scintigraphic methods. The .sup.111 Indium-oxine method is time consuming, delaying rapid diagnosis of the occult abscess. It also requires highly skilled personnel and specialized facilities to perform the separation and labeling. Additionally, the radiolabeled leukocytes must be quickly used or they will not be viable.
Antibodies are known for various purposes such as localization of tumors, detection of vascular clots and detection of infection and inflammation. Monoclonal antibodies produced from hybridomas are often used in these methods because of the specificity with which they will bind to target molecules and cells.
Thakur et al. Nucl. Med. Biol. 14: 51-58, 1987, evaluated the use of radiolabeled monoclonal antibodies specific for human platelet antigenic determinants to detect thrombi.
In Thakur, Research in Progress: FY 1986 Summaries of Projects Sponsored by the Office of Health and Environmental Research, Office of Scientific and Technical Information, Jan. 1986, it is stated that Thakur will be developing methods of radiolabeling human neutrophils, platelets and lymphocytes selectively in whole blood.
In Richard and Thakur, J. Nucl. Med. 28: abstract no. 693, (1987), four bifunctional chelating agents were tested for binding with SSEA-1 antibodies as a tracer for human neutrophils.
Thakur et al. J. Nucl. Med. 28: abstract no. 419, (1987) evaluated bimane analogues for use as chelating agents for radiolabels and proteins.
Locher et al, Nuclear Medicine Communications 7: 659-670, (1986) used radiolabeled monoclonal antibodies directed against human granulocytes to detect inflammatory and infectious lesions. These researchers intravenously infused .sup.123 Iodine labeled monoclonal antibodies and waited for them to accumulate at a suspected area of infection. The radiolabel was then detected using a gamma camera. Areas of infection were located at expected sites.
U.S. Pat. 4,634,586 issued Jan. 6, 1987 to Goodwin and Meares discloses a reagent and method for radioimaging leukocytes. In this method leukocytes are radioimmunoimaged by injecting patients with an immunoreactive nonleukocidal conjugate of an anti-leukocyte antibody and a gamma-emitting radioactive metal chelate, waiting for the conjugate to localize on the leukocytes, injecting the patient with an antibody to the conjugate to clear the blood of background nonlocalized conjugate and visualizing the leukocytes by scintillation scanning. The method can also be used without the step of injecting an antibody to clear background nonlocalized antibody.
U.S. Pat. 4,636,380 issued Jan. 13, 1987 to Wong discloses a method of directly labeling proteinaceous substances with .sup.111 Indium or .sup.111 Indium for use in scintigraphic imaging of thrombi, emboli, infectious lesions, tumors, myocardial infarction and vascular abnormalities.
U.S. Pat. 4,444,744 issued April 24, 1984 to Goldenberg discloses the use of radiolabeled antibodies to tumor cell surface antigens for the detection, localization and therapy of tumors.
U.S. Pat. 4,460,561 issued July 17, 1984 to Goldenberg discloses the use of radiolabeled antibodies specific intracellular tumor-associated markers for the detection, localization and therapy of tumors.
Other U.S. Pats. such as 4,427,646 (Olexa et al.)and 4,647,445 (Lees) disclose the use of radiolabeled proteins or lipoproteins in radiographic detection of illness.
Agents and methods useful for associating the an antibody or other protein to a radiolabel have been disclosed in various U.S. patents.
U.S. Pat. 4,479,930 issued Oct. 30, 1984 to Hnatowich discloses methods of coupling amines such as polypeptides and proteins to radiolabels using a dicyclic dianhydride of compounds such as ethylenediaminetetraacetic acid or diethylenetriaminepentaacetic acid. The patent also discloses chemical compositions containing the chelating agents and proteins or polypeptides.
U.S. Pat. 4,668,503 issued May 26, 1987 to Hnatowich discloses a process for labeling amines such as antibodies, proteins and polypeptides with .sup.99m Technetium in the presence of a stannous reducing agent.
U.S. Pat. 4,622,420 issued Nov. 11, 1986 to Meares et al. discloses chelating agents which are analogs of ethylenediaminetetraacetic acid, ethylenediaminetriacetic acid or ethylenediaminepentaacetic acid which are useful in attaching radiolabels to biological molecules such as proteins.
Other U.S. Pats. such as 4,678,667 (Meares et al.), 4,707,352 (Stavrianpoulos), 4,421,735 (Haber et al.), 4,434,151 (Byrne et al.) and 4,575,556 (Byrne et al.) also disclose chelating agents which can be used to link proteins such as antibodies and radiolabels for use in detecting pathological conditions.
U.S. Pat. 4,652,519 issued March 24, 1987 to Warshawsky et al. discloses bifunctional chelating agents which can be used in radioimmunoassays and the like.
U.S. Pat. 4,671,958 issued June 9, 1987 to Rodwell et al. discloses polypeptide linkers for use in linking antibodies and compounds such as therapeutic compounds and radiopharmaceuticals which are then transported to target locations in the body.
Although some of these methods may detect infections and inflammations, improved immunoreagents which are specific for cell types such as neutrophils which accumulate at sites of infection and inflammation but which will not bind to other types of cells in appreciable amounts and give high background readings are still needed. Accordingly, it is an object of the invention to provide improved methods and reagents for detecting occult abscesses and inflammation. It is also an object of the invention to provide improved reagents for the detection of occult abscesses and inflammation which have a high specificity for neutrophils, a type of granulocyte cell which accumulates at the site of infection or inflammation.